Unless you elected to be taxed as a corporation, yes, that was a mistake.
But as long as you gave them the EIN you will be using on the SMLLC, it shouldn't make a difference on your return. You should give them an updated correct W9 though. You can print one form the IRS website and fil it in and send back to them.
♪♫•*¨*•.¸¸♥Lisa♥ ¸¸.•*¨*•♫♪
